drivers/hid/hid-google-hammer.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  HID driver for Google Hammer device.
   4  *
   5  *  Copyright (c) 2017 Google Inc.
   6  *  Author: Wei-Ning Huang <wnhuang@google.com>
   7  */
   8
   9 /*
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License as published by the Free
  12  * Software Foundation; either version 2 of the License, or (at your option)
  13  * any later version.
  14  */
  15
  16 #include <linux/acpi.h>
  17 #include <linux/hid.h>
  18 #include <linux/leds.h>
  19 #include <linux/module.h>
  20 #include <linux/platform_data/cros_ec_commands.h>
  21 #include <linux/platform_data/cros_ec_proto.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/pm_wakeup.h>
  24 #include <asm/unaligned.h>
  25
  26 #include "hid-ids.h"
  27
  28 /*
  29  * C(hrome)B(ase)A(ttached)S(witch) - switch exported by Chrome EC and reporting
  30  * state of the "Whiskers" base - attached or detached. Whiskers USB device also
  31  * reports position of the keyboard - folded or not. Combining base state and
  32  * position allows us to generate proper "Tablet mode" events.
  33  */
  34 struct cbas_ec {
  35         struct device *dev;     /* The platform device (EC) */
  36         struct input_dev *input;
  37         bool base_present;
  38         bool base_folded;
  39         struct notifier_block notifier;
  40 };
  41
  42 static struct cbas_ec cbas_ec;
  43 static DEFINE_SPINLOCK(cbas_ec_lock);
  44 static DEFINE_MUTEX(cbas_ec_reglock);
  45
  46 static bool cbas_parse_base_state(const void *data)
  47 {
  48         u32 switches = get_unaligned_le32(data);
  49
  50         return !!(switches & BIT(EC_MKBP_BASE_ATTACHED));
  51 }
  52
  53 static int cbas_ec_query_base(struct cros_ec_device *ec_dev, bool get_state,
  54                                   bool *state)
  55 {
  56         struct ec_params_mkbp_info *params;
  57         struct cros_ec_command *msg;
  58         int ret;
  59
  60         msg = kzalloc(sizeof(*msg) + max(sizeof(u32), sizeof(*params)),
  61                       GFP_KERNEL);
  62         if (!msg)
  63                 return -ENOMEM;
  64
  65         msg->command = EC_CMD_MKBP_INFO;
  66         msg->version = 1;
  67         msg->outsize = sizeof(*params);
  68         msg->insize = sizeof(u32);
  69         params = (struct ec_params_mkbp_info *)msg->data;
  70         params->info_type = get_state ?
  71                 EC_MKBP_INFO_CURRENT : EC_MKBP_INFO_SUPPORTED;
  72         params->event_type = EC_MKBP_EVENT_SWITCH;
  73
  74         ret = cros_ec_cmd_xfer_status(ec_dev, msg);
  75         if (ret >= 0) {
  76                 if (ret != sizeof(u32)) {
  77                         dev_warn(ec_dev->dev, "wrong result size: %d != %zu\n",
  78                                  ret, sizeof(u32));
  79                         ret = -EPROTO;
  80                 } else {
  81                         *state = cbas_parse_base_state(msg->data);
  82                         ret = 0;
  83                 }
  84         }
  85
  86         kfree(msg);
  87
  88         return ret;
  89 }
  90
  91 static int cbas_ec_notify(struct notifier_block *nb,
  92                               unsigned long queued_during_suspend,
  93                               void *_notify)
  94 {
  95         struct cros_ec_device *ec = _notify;
  96         unsigned long flags;
  97         bool base_present;
  98
  99         if (ec->event_data.event_type == EC_MKBP_EVENT_SWITCH) {
 100                 base_present = cbas_parse_base_state(
 101                                         &ec->event_data.data.switches);
 102                 dev_dbg(cbas_ec.dev,
 103                         "%s: base: %d\n", __func__, base_present);
 104
 105                 if (device_may_wakeup(cbas_ec.dev) ||
 106                     !queued_during_suspend) {
 107
 108                         pm_wakeup_event(cbas_ec.dev, 0);
 109
 110                         spin_lock_irqsave(&cbas_ec_lock, flags);
 111
 112                         /*
 113                          * While input layer dedupes the events, we do not want
 114                          * to disrupt the state reported by the base by
 115                          * overriding it with state reported by the LID. Only
 116                          * report changes, as we assume that on attach the base
 117                          * is not folded.
 118                          */
 119                         if (base_present != cbas_ec.base_present) {
 120                                 input_report_switch(cbas_ec.input,
 121                                                     SW_TABLET_MODE,
 122                                                     !base_present);
 123                                 input_sync(cbas_ec.input);
 124                                 cbas_ec.base_present = base_present;
 125                         }
 126
 127                         spin_unlock_irqrestore(&cbas_ec_lock, flags);
 128                 }
 129         }
 130
 131         return NOTIFY_OK;
 132 }
 133
 134 static __maybe_unused int cbas_ec_resume(struct device *dev)
 135 {
 136         struct cros_ec_device *ec = dev_get_drvdata(dev->parent);
 137         bool base_present;
 138         int error;
 139
 140         error = cbas_ec_query_base(ec, true, &base_present);
 141         if (error) {
 142                 dev_warn(dev, "failed to fetch base state on resume: %d\n",
 143                          error);
 144         } else {
 145                 spin_lock_irq(&cbas_ec_lock);
 146
 147                 cbas_ec.base_present = base_present;
 148
 149                 /*
 150                  * Only report if base is disconnected. If base is connected,
 151                  * it will resend its state on resume, and we'll update it
 152                  * in hammer_event().
 153                  */
 154                 if (!cbas_ec.base_present) {
 155                         input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
 156                         input_sync(cbas_ec.input);
 157                 }
 158
 159                 spin_unlock_irq(&cbas_ec_lock);
 160         }
 161
 162         return 0;
 163 }
 164
 165 static SIMPLE_DEV_PM_OPS(cbas_ec_pm_ops, NULL, cbas_ec_resume);
 166
 167 static void cbas_ec_set_input(struct input_dev *input)
 168 {
 169         /* Take the lock so hammer_event() does not race with us here */
 170         spin_lock_irq(&cbas_ec_lock);
 171         cbas_ec.input = input;
 172         spin_unlock_irq(&cbas_ec_lock);
 173 }
 174
 175 static int __cbas_ec_probe(struct platform_device *pdev)
 176 {
 177         struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
 178         struct input_dev *input;
 179         bool base_supported;
 180         int error;
 181
 182         error = cbas_ec_query_base(ec, false, &base_supported);
 183         if (error)
 184                 return error;
 185
 186         if (!base_supported)
 187                 return -ENXIO;
 188
 189         input = devm_input_allocate_device(&pdev->dev);
 190         if (!input)
 191                 return -ENOMEM;
 192
 193         input->name = "Whiskers Tablet Mode Switch";
 194         input->id.bustype = BUS_HOST;
 195
 196         input_set_capability(input, EV_SW, SW_TABLET_MODE);
 197
 198         error = input_register_device(input);
 199         if (error) {
 200                 dev_err(&pdev->dev, "cannot register input device: %d\n",
 201                         error);
 202                 return error;
 203         }
 204
 205         /* Seed the state */
 206         error = cbas_ec_query_base(ec, true, &cbas_ec.base_present);
 207         if (error) {
 208                 dev_err(&pdev->dev, "cannot query base state: %d\n", error);
 209                 return error;
 210         }
 211
 212         if (!cbas_ec.base_present)
 213                 cbas_ec.base_folded = false;
 214
 215         dev_dbg(&pdev->dev, "%s: base: %d, folded: %d\n", __func__,
 216                 cbas_ec.base_present, cbas_ec.base_folded);
 217
 218         input_report_switch(input, SW_TABLET_MODE,
 219                             !cbas_ec.base_present || cbas_ec.base_folded);
 220
 221         cbas_ec_set_input(input);
 222
 223         cbas_ec.dev = &pdev->dev;
 224         cbas_ec.notifier.notifier_call = cbas_ec_notify;
 225         error = blocking_notifier_chain_register(&ec->event_notifier,
 226                                                  &cbas_ec.notifier);
 227         if (error) {
 228                 dev_err(&pdev->dev, "cannot register notifier: %d\n", error);
 229                 cbas_ec_set_input(NULL);
 230                 return error;
 231         }
 232
 233         device_init_wakeup(&pdev->dev, true);
 234         return 0;
 235 }
 236
 237 static int cbas_ec_probe(struct platform_device *pdev)
 238 {
 239         int retval;
 240
 241         mutex_lock(&cbas_ec_reglock);
 242
 243         if (cbas_ec.input) {
 244                 retval = -EBUSY;
 245                 goto out;
 246         }
 247
 248         retval = __cbas_ec_probe(pdev);
 249
 250 out:
 251         mutex_unlock(&cbas_ec_reglock);
 252         return retval;
 253 }
 254
 255 static int cbas_ec_remove(struct platform_device *pdev)
 256 {
 257         struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
 258
 259         mutex_lock(&cbas_ec_reglock);
 260
 261         blocking_notifier_chain_unregister(&ec->event_notifier,
 262                                            &cbas_ec.notifier);
 263         cbas_ec_set_input(NULL);
 264
 265         mutex_unlock(&cbas_ec_reglock);
 266         return 0;
 267 }
 268
 269 static const struct acpi_device_id cbas_ec_acpi_ids[] = {
 270         { "GOOG000B", 0 },
 271         { }
 272 };
 273 MODULE_DEVICE_TABLE(acpi, cbas_ec_acpi_ids);
 274
 275 static struct platform_driver cbas_ec_driver = {
 276         .probe = cbas_ec_probe,
 277         .remove = cbas_ec_remove,
 278         .driver = {
 279                 .name = "cbas_ec",
 280                 .acpi_match_table = ACPI_PTR(cbas_ec_acpi_ids),
 281                 .pm = &cbas_ec_pm_ops,
 282         },
 283 };
 284
 285 #define MAX_BRIGHTNESS 100
 286
 287 struct hammer_kbd_leds {
 288         struct led_classdev cdev;
 289         struct hid_device *hdev;
 290         u8 buf[2] ____cacheline_aligned;
 291 };
 292
 293 static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
 294                 enum led_brightness br)
 295 {
 296         struct hammer_kbd_leds *led = container_of(cdev,
 297                                                    struct hammer_kbd_leds,
 298                                                    cdev);
 299         int ret;
 300
 301         led->buf[0] = 0;
 302         led->buf[1] = br;
 303
 304         /*
 305          * Request USB HID device to be in Full On mode, so that sending
 306          * hardware output report and hardware raw request won't fail.
 307          */
 308         ret = hid_hw_power(led->hdev, PM_HINT_FULLON);
 309         if (ret < 0) {
 310                 hid_err(led->hdev, "failed: device not resumed %d\n", ret);
 311                 return ret;
 312         }
 313
 314         ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
 315         if (ret == -ENOSYS)
 316                 ret = hid_hw_raw_request(led->hdev, 0, led->buf,
 317                                          sizeof(led->buf),
 318                                          HID_OUTPUT_REPORT,
 319                                          HID_REQ_SET_REPORT);
 320         if (ret < 0)
 321                 hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
 322                         ret);
 323
 324         /* Request USB HID device back to Normal Mode. */
 325         hid_hw_power(led->hdev, PM_HINT_NORMAL);
 326
 327         return ret;
 328 }
 329
 330 static int hammer_register_leds(struct hid_device *hdev)
 331 {
 332         struct hammer_kbd_leds *kbd_backlight;
 333         int error;
 334
 335         kbd_backlight = kzalloc(sizeof(*kbd_backlight), GFP_KERNEL);
 336         if (!kbd_backlight)
 337                 return -ENOMEM;
 338
 339         kbd_backlight->hdev = hdev;
 340         kbd_backlight->cdev.name = "hammer::kbd_backlight";
 341         kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
 342         kbd_backlight->cdev.brightness_set_blocking =
 343                 hammer_kbd_brightness_set_blocking;
 344         kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
 345
 346         /* Set backlight to 0% initially. */
 347         hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
 348
 349         error = led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
 350         if (error)
 351                 goto err_free_mem;
 352
 353         hid_set_drvdata(hdev, kbd_backlight);
 354         return 0;
 355
 356 err_free_mem:
 357         kfree(kbd_backlight);
 358         return error;
 359 }
 360
 361 static void hammer_unregister_leds(struct hid_device *hdev)
 362 {
 363         struct hammer_kbd_leds *kbd_backlight = hid_get_drvdata(hdev);
 364
 365         if (kbd_backlight) {
 366                 led_classdev_unregister(&kbd_backlight->cdev);
 367                 kfree(kbd_backlight);
 368         }
 369 }
 370
 371 #define HID_UP_GOOGLEVENDOR     0xffd10000
 372 #define HID_VD_KBD_FOLDED       0x00000019
 373 #define HID_USAGE_KBD_FOLDED    (HID_UP_GOOGLEVENDOR | HID_VD_KBD_FOLDED)
 374
 375 /* HID usage for keyboard backlight (Alphanumeric display brightness) */
 376 #define HID_AD_BRIGHTNESS       0x00140046
 377
 378 static int hammer_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 379                                 struct hid_field *field,
 380                                 struct hid_usage *usage,
 381                                 unsigned long **bit, int *max)
 382 {
 383         if (usage->hid == HID_USAGE_KBD_FOLDED) {
 384                 /*
 385                  * We do not want to have this usage mapped as it will get
 386                  * mixed in with "base attached" signal and delivered over
 387                  * separate input device for tablet switch mode.
 388                  */
 389                 return -1;
 390         }
 391
 392         return 0;
 393 }
 394
 395 static int hammer_event(struct hid_device *hid, struct hid_field *field,
 396                         struct hid_usage *usage, __s32 value)
 397 {
 398         unsigned long flags;
 399
 400         if (usage->hid == HID_USAGE_KBD_FOLDED) {
 401                 spin_lock_irqsave(&cbas_ec_lock, flags);
 402
 403                 /*
 404                  * If we are getting events from Whiskers that means that it
 405                  * is attached to the lid.
 406                  */
 407                 cbas_ec.base_present = true;
 408                 cbas_ec.base_folded = value;
 409                 hid_dbg(hid, "%s: base: %d, folded: %d\n", __func__,
 410                         cbas_ec.base_present, cbas_ec.base_folded);
 411
 412                 if (cbas_ec.input) {
 413                         input_report_switch(cbas_ec.input,
 414                                             SW_TABLET_MODE, value);
 415                         input_sync(cbas_ec.input);
 416                 }
 417
 418                 spin_unlock_irqrestore(&cbas_ec_lock, flags);
 419                 return 1; /* We handled this event */
 420         }
 421
 422         return 0;
 423 }
 424
 425 static bool hammer_has_usage(struct hid_device *hdev, unsigned int report_type,
 426                         unsigned application, unsigned usage)
 427 {
 428         struct hid_report_enum *re = &hdev->report_enum[report_type];
 429         struct hid_report *report;
 430         int i, j;
 431
 432         list_for_each_entry(report, &re->report_list, list) {
 433                 if (report->application != application)
 434                         continue;
 435
 436                 for (i = 0; i < report->maxfield; i++) {
 437                         struct hid_field *field = report->field[i];
 438
 439                         for (j = 0; j < field->maxusage; j++)
 440                                 if (field->usage[j].hid == usage)
 441                                         return true;
 442                 }
 443         }
 444
 445         return false;
 446 }
 447
 448 static bool hammer_has_folded_event(struct hid_device *hdev)
 449 {
 450         return hammer_has_usage(hdev, HID_INPUT_REPORT,
 451                                 HID_GD_KEYBOARD, HID_USAGE_KBD_FOLDED);
 452 }
 453
 454 static bool hammer_has_backlight_control(struct hid_device *hdev)
 455 {
 456         return hammer_has_usage(hdev, HID_OUTPUT_REPORT,
 457                                 HID_GD_KEYBOARD, HID_AD_BRIGHTNESS);
 458 }
 459
 460 static int hammer_probe(struct hid_device *hdev,
 461                         const struct hid_device_id *id)
 462 {
 463         int error;
 464
 465         error = hid_parse(hdev);
 466         if (error)
 467                 return error;
 468
 469         error = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 470         if (error)
 471                 return error;
 472
 473         /*
 474          * We always want to poll for, and handle tablet mode events from
 475          * devices that have folded usage, even when nobody has opened the input
 476          * device. This also prevents the hid core from dropping early tablet
 477          * mode events from the device.
 478          */
 479         if (hammer_has_folded_event(hdev)) {
 480                 hdev->quirks |= HID_QUIRK_ALWAYS_POLL;
 481                 error = hid_hw_open(hdev);
 482                 if (error)
 483                         return error;
 484         }
 485
 486         if (hammer_has_backlight_control(hdev)) {
 487                 error = hammer_register_leds(hdev);
 488                 if (error)
 489                         hid_warn(hdev,
 490                                 "Failed to register keyboard backlight: %d\n",
 491                                 error);
 492         }
 493
 494         return 0;
 495 }
 496
 497 static void hammer_remove(struct hid_device *hdev)
 498 {
 499         unsigned long flags;
 500
 501         if (hammer_has_folded_event(hdev)) {
 502                 hid_hw_close(hdev);
 503
 504                 /*
 505                  * If we are disconnecting then most likely Whiskers is
 506                  * being removed. Even if it is not removed, without proper
 507                  * keyboard we should not stay in clamshell mode.
 508                  *
 509                  * The reason for doing it here and not waiting for signal
 510                  * from EC, is that on some devices there are high leakage
 511                  * on Whiskers pins and we do not detect disconnect reliably,
 512                  * resulting in devices being stuck in clamshell mode.
 513                  */
 514                 spin_lock_irqsave(&cbas_ec_lock, flags);
 515                 if (cbas_ec.input && cbas_ec.base_present) {
 516                         input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
 517                         input_sync(cbas_ec.input);
 518                 }
 519                 cbas_ec.base_present = false;
 520                 spin_unlock_irqrestore(&cbas_ec_lock, flags);
 521         }
 522
 523         hammer_unregister_leds(hdev);
 524
 525         hid_hw_stop(hdev);
 526 }
 527
 528 static const struct hid_device_id hammer_devices[] = {
 529         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 530                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
 531         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 532                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MAGNEMITE) },
 533         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 534                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MASTERBALL) },
 535         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 536                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
 537         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 538                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
 539         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 540                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WHISKERS) },
 541         { }
 542 };
 543 MODULE_DEVICE_TABLE(hid, hammer_devices);
 544
 545 static struct hid_driver hammer_driver = {
 546         .name = "hammer",
 547         .id_table = hammer_devices,
 548         .probe = hammer_probe,
 549         .remove = hammer_remove,
 550         .input_mapping = hammer_input_mapping,
 551         .event = hammer_event,
 552 };
 553
 554 static int __init hammer_init(void)
 555 {
 556         int error;
 557
 558         error = platform_driver_register(&cbas_ec_driver);
 559         if (error)
 560                 return error;
 561
 562         error = hid_register_driver(&hammer_driver);
 563         if (error) {
 564                 platform_driver_unregister(&cbas_ec_driver);
 565                 return error;
 566         }
 567
 568         return 0;
 569 }
 570 module_init(hammer_init);
 571
 572 static void __exit hammer_exit(void)
 573 {
 574         hid_unregister_driver(&hammer_driver);
 575         platform_driver_unregister(&cbas_ec_driver);
 576 }
 577 module_exit(hammer_exit);
 578
 579 MODULE_LICENSE("GPL");